Conventionally, air conditioning systems having multiple air conditioners and a control device thereof connected via a general-purpose network are sometimes installed in large-scale buildings, such as a retail store or an office building. The control device controls the multiple air conditioners in accordance with a preset algorithm. It is disclosed that a system controls indoor device (indoor units) divided into multiple groups beforehand, group by group in order to control the multiple indoor device (indoor units) in a building with minimal operation (see, for example, Patent Literatures 1 and 2).
Moreover, a central managing system that collectively control the multiple air conditioners is required to comprehend the system linkage of the air conditioners. Hence, a central managing system that automatically recognizes a system linkage is disclosed (see, for example, Patent Literature 3).